Help Center/ Simple Message Notification/ FAQs/ What Are the Limitations on SMS Messages?
Updated on 2024-12-05 GMT+08:00
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What Are the Limitations on SMS Messages?

  • The following table describes the rules for calculating the number of characters in an SMS message.

    SMS Type

    Character Counting Rule

    Remarks

    International SMSs (sent to mobile numbers outside the Chinese mainland)

    SMSs in English:

    • GSM-7 characters are used for counting.
    • If an SMS contains 160 characters or less, it is counted as one SMS.

      If an SMS contains more than 160 characters, every 153 characters are counted as one SMS.
    • If an SMS contains 158 English characters, it is counted as one SMS. If an SMS contains 164 (153 + 11) characters, it is counted as two SMSs. If an SMS contains 320 (153 + 153 + 14) characters, it is counted as three SMSs.
    • For example, if an SMS template contains variable ${NUM_8} set to 123456, that variable is counted as six characters.

    SMSs in other languages:

    • Each Unicode character, such as a letter, digit, punctuation (full-width and half-width), and space, is counted as one character.
    • If an SMS contains 70 characters or less, it is counted as one SMS.

      If an SMS contains more than 70 characters, every 67 characters are counted as one SMS.

    Chinese Mainland SMSs (sent to Chinese mainland mobile numbers)
    • Each Unicode character, such as a letter, digit, punctuation (full-width and half-width), and space, is counted as one character.
    • Length of an SMS = The number of characters in an SMS template + The number of characters in the signature
    • If an SMS contains 70 characters or less, it is counted as one SMS.

      If an SMS contains more than 70 characters, every 67 characters are counted as one SMS.
    • Each letter and digit in a signature is counted as a character. For example, [HUAWEI] is counted as eight characters.
    • For example, if an SMS template contains variable ${NUM_8} set to 123456, that variable is counted as six characters.

    For details, see SMS Length Calculation in Message & SMS User Guide.

  • Special characters such as square brackets ([]) are not allowed in SMS messages sent to mobile numbers in the Chinese mainland. For details, see Template and Variable Specifications in Message & SMS User Guide.